We've been running episerver 5 enterprise on a site without globalization, but each site did have it's own language and lang-files. The matching of language with lang-files is done by using the language-code specified in the sites list in web.config
After upgrading to episerver 6 this worked initially but started causing problems - Simple addresses started causing problems because the language code for the simple-url didn't match the language-code specified in web.config, and the keyword-database for lucene broke with the same kind of errors.
This workaround was to enable globalization and giving each site one - and only one language - so it wasn't terribly useful. So the question is, was our previous setup based upon broken functionality in episerver or has it been corrected for certain scenarios and caused problems for setup?